/Engine/Source/Runtime/Core/Public/Serialization/PackageWriter.h
Write the PackageTrailer, a separate segment for some bulkdata that is written the end of the file.
void WritePackageTrailer ( const [FPackageTrailerInfo](API\Runtime\Core\Serialization\IPackageWriter\FPackageTrailerInfo) & Info, const [FIoBuffer](API\Runtime\Core\IO\FIoBuffer) & Data )